The present invention relates, in general, to shrouds or hoods for use with dust creating machines, and, in particular, to shrouds or hoods for use with abrading machines.
Dust creating machines such as grinding machines having grinding wheels are notorious for producing dust-laden air, grit and metal particles during operation. Dust shrouds that partially envelop grinding wheels were developed in order to reduce some of this pollution by drawing the dust, grit and metal particles through the dust shroud using a remote vacuum operated exhaust system. By employing a dust shroud connected to a vacuum, much of the dust-laden air resultant from wheel rotation during operational use can be effectively removed away from the area of the grinding wheel and the machine operator. An example of such a dust shroud is disclosed in U.S. Pat. No. 4,192,104 to Patenaude.
The manufactured dust shroud corresponding to U.S. Pat. No. 4,192,104 is equipped with an inspection or access door that facilitates inspection and changing of the grinding wheel. The access door is hinged to a front wall of the dust shroud housing at the top or sides of an opening in the front wall of the housing. A problem with a hinged access door is that the workpiece or other equipment positioned directly in front of the hinged access door impedes an operator""s ability to open the door.
Another disadvantage of the hinged access door is that it can only be maintained in either a filly closed position or a fully open position (if specially rigged), and can not be maintained in a partially opened position. Quite often, it is desirable to have the hinged access door at least partially open during operation of the grinding wheel in order to surface grind certain workpieces or to inspect the wheel. Because the hinged door can not be maintained in a partially opened position, when it is desirable for the hinged door to be in a partially opened position, the hinged door must be rigged so that it is in a filly open position. Most of the suction power that is provided by the vacuum source is lost when the hinged door is in the fully open position, rendering the shroud ineffective. Further, with the hinged door in the fully open position, the operator""s personal safety is compromised during use because the grinding wheel is not covered and the operator""s health is compromised because dust, grit and metal particles are allowed to blow out of the opening in the front wall of the housing, into the operator. Therefore, the present inventor has recognized a need exists for an adjustable dust shroud access door that is capable of being selectively positioned for a variety of partially opened conditions.
A further disadvantage of the manufactured dust shroud corresponding to U.S. Pat. No. 4,192,104 is that it is made by a sand casting process. Sand casting requires a new mold construction for each shroud produced and necessitates a considerable amount of clean up. As a result, the sand casting manufacturing process is slow, labor intensive and costly. Also, the sand casting process is incapable of producing a light-weight shroud construction for several reasons. First, larger and thicker amounts of molten material are required to prevent the molten material from inadvertently hardening during introduction of the molten material into the mold. Second, the sand casting process is incapable of producing thin wall sections, which are required to produce a lighter weight dust shroud. The present inventor has recognized that a light-weight shroud would be easier to handle and extend the life of all grinding machine components prone to premature wear and failure caused by unnecessarily heavy dust shrouds.
In addition, the rough, porous sand cast finish on the dust shroud has proven to be detrimental to the performance of the shroud because it causes the particles of dust, grit and metal to stick to the porous walls of the interior vacuum channels. Inevitably, the dust, grit and metal build-up causes a slower air speed of dust-laden air through the shroud, resulting in a reduction in the interior volume of the vacuum channels of the shroud. Occasionally, a complete restriction of the vacuum channels and a loss of all suction power occurs if the housing is not effectively unclogged. Once the housing begins to clog up, it is difficult or impossible to service since it is a one-piece design and can not be taken apart for a proper cleaning. Consequently, the present inventor has recognized a need exists to manufacture a multi-piece dust shroud using an improved, cost-efficient process that produces a better dust shroud.
An aspect of the invention involves a dust shroud for use with a vacuum source and an abrading machine having a rotating abrading wheel. The dust shroud includes a dust shroud housing adapted to be connected to the vacuum source and mounted to the abrading machine. The dust shroud housing includes a front wall with a front opening through which the abrading wheel may be accessed. A sliding door is slidably mounted to the front wall of the dust shroud housing for selectively covering the front opening.
Another aspect of the invention involves a sliding door assembly for a dust shroud. The dust shroud is adapted for use with a vacuum source and an abrading machine having a rotating abrading wheel. The dust shroud includes a dust shroud housing having a front wall with a front opening through which the abrading wheel may be accessed. The sliding door assembly includes a sliding door adapted to be slidably mounted to the front wall of the dust shroud housing for selectively covering the front opening. In one implementation, the front wall of the housing includes a mounting portion integrated with the front wall, and the sliding door is adapted to be slidably mounted to the mounting portion. In an alternative implementation, the sliding door assembly further includes an adapter bracket adapted to be mounted to the front wall and slidably receive the sliding door.
An additional aspect of the invention involves a method of controlling the size of a front access opening of a front wall of a dust shroud, where the dust shroud is for use with a vacuum source and an abrading machine having a rotating abrading wheel. The method includes providing a sliding door slidably mounted to the front wall of the dust shroud, and sliding the door to a location that minimizes the interference with a workpiece, but maximizes vacuum suction. In one implementation, the dust shroud includes a mounting portion integrated with the front wall, and providing a sliding door includes the step of providing a sliding door slidably mounted to the mounting portion. In an alternative implementation, the dust shroud includes an adapter bracket mounted to the front wall, and providing a sliding door includes the step of providing a sliding door slidably mounted to the adapter bracket.
A further aspect of the invention involves a method of retrofitting a sliding door assembly to a dust shroud, where the dust shroud is for use with a vacuum source and an abrading machine having a rotating abrading wheel. The dust shroud includes a dust shroud housing having a front wall with a front opening through which the abrading wheel may be accessed. The method includes removing a hinged door from the front wall of the dust shroud, and mounting a sliding door assembly to the front wall, the sliding door assembly including an adapter bracket and a slidable door adapted to be slidably received by the adapter bracket.
Another aspect of the invention involves a method of manufacturing a dust shroud for use with a vacuum source and an abrading machine having a rotating abrading wheel. The method includes die casting a front dust shroud housing portion, die casting a rear dust shroud housing portion, and attaching the front and rear dust shroud housing portions together to form a dust shroud housing.
An additional aspect of the invention involves a bracket assembly for mounting a dust shroud to an abrading machine. The dust shroud includes an alignment bar. The abrading machine includes a spindle housing with a circular portion surrounding a spindle adapted to carry an abrading wheel. The bracket assembly includes a circular clamp section adapted to be rotatably mounted to the circular portion of the spindle housing for rotatable angular adjustability of the dust shroud relative to the abrading wheel, and a forked portion adapted to receive the alignment bar of the dust shroud for radial adjustability of the dust shroud relative to the abrading wheel.
Another aspect of the invention involves a method of mounting a dust shroud to an abrading machine. The method includes rotatably mounting a circular clamp section of a bracket assembly to a circular portion of a spindle housing of the abrading machine, and radially mounting an alignment bar of the dust shroud to a forked portion of the bracket assembly.
A further aspect of the invention involves a bracket assembly for mounting a dust shroud having an alignment bar to an abrading machine having a spindle housing with a spindle adapted to carry an abrading wheel. The bracket assembly includes a circular adapter adapted to be mounted to the spindle housing around the spindle, a bracket including a circular clamp section adapted to be rotatably mounted to the circular adapter for rotatable angular adjustability of the dust shroud relative to the abrading wheel, and a forked portion adapted to receive the alignment bar of the dust shroud for radial adjustability of the dust shroud relative to the abrading wheel.
A still further aspect of the invention involves a method of mounting a dust shroud to an abrading machine. The method includes mounting a circular adapter of a bracket assembly to a spindle housing of an abrading machine, around a spindle of the spindle housing, rotatably mounting a circular clamp section of a bracket to the circular adapter, and radially mounting an alignment bar of a dust shroud to a forked portion of the bracket.
Other features and advantages of the invention will be evident from reading the following detailed description, which is intended to illustrate, but not limit, the invention.